1. Field of the Invention
An object of the present invention is a device for the counting of chip cards, or also memory cards, contained in a batch, or preferably even contained in a sealed box. It can be applied more particularly in the field of computerised money systems. Its main advantage is that it increases the security of the counting operation, during the manufacture and distribution of the cards, as regards both the precision of the number of cards counted and the handling of the cards in this batch.
In most chip card applications, the cards represent either a direct monetary value (as with prepaid cards such as telephone cards for example) or a substantial transactional capacity (as with bank or access type cards). In all uses, the chip cards provide additional security in the applications to which they are related. One of the key factors in guaranteeing this security, during the manufacture of the cards, is the precise counting of the number of cards, good as well as defective, that have been manufactured. This counting is done at each step of manufacture, especially at the encoding of the cards, when they assume their value, and especially also when these cards are dispatched from the manufacture to the user.
The following constraints of security have to be met for the counting operation. Firstly, it is necessary to obtain a counting error rate that is ideally zero and should, in practice, be better than one in a million. Besides, the counting should be reliable, i.e. it should not, in itself, introduce risks of error during the handling operations which may depend on the counting operator. Indeed, there is always a risk of fraud when human operators have to handle the cards in a manufacturing system. Finally, the counting should be fast so that it can be done at the end of each of the manufacturing steps and on the entire manufactured batch, without concerning only one sampled part. The number of cards manufactured in one manufacturing unit may be of the order of several millions per month, and it can be said that they have to be counted at least three times during the manufacturing cycle. The problems entailed by this operation can therefore be imagined.
2. Description of the Prior Art
The existing systems used to count cards are, firstly, manual type systems and, secondly, optical type systems. With manual counting, the error rate is very high: it is in the range of one per thousand to one per ten thousand. Besides, these manual counting operations are very slow and have the obvious drawback of requiring action by an operator. Optical methods also include the known one in which cards are counted as they individually flow past a photoelectric cell. This counting can be used to obtain error rates only of the order of one per hundred thousand to one per million. This precision is far greater than the earlier one, but this technique does not remove risks of error or fraud when the cards are being unpacked or returned to their boxes (after the counting). This unpacking is necessary to set up a certain distance between the cards.
Besides, another optical type of method envisages the counting of the cards in the boxes that contain them. In effect, in a batch of cards placed flat against one another in a box, a variation can be observed in the transmission of light. This phenomenon is caused by the edges of the different cards that are placed side by side with another. This variation in light can be detected by a counter connected to an optical sensor placed on the other side of the batch. In this approach that uses transmission, the manufacture of the card structure of the cards should be of the co-laminated type. It may be recalled that, to manufacture a co-laminated card structure, different layers of plastic film are used, stacked one on top of the other until the overall thickness is equal to that desired. The layers are not all of the same type. Firstly, some of them have a perforation designed to constitute a cavity, with the others, to receive the integrated circuit of the chip card and, secondly, in order to facilitate the counting process, some of these layers are made of a material transparent to light radiation, preferably to ultraviolet radiation. It is then enough to present a card such as this, on its edge, before an ultraviolet radiation to allow a thin beam of light, that has crossed the transparent layer, to appear. If one batch of cards includes cards stacked one against the other, then counting the number of light beams that go through the batch is sufficient to obtain the number of cards contained in this batch.
The latter technique, however, has the following drawbacks. Firstly, the adjusting of the light detection operations and of the way in which the cards are presented is delicate and unstable. Secondly, since the boxes that contain the batches of cards are not closed (as the light radiation has to go through them), the risk of fraud is not eliminated. Finally, and above all, this technique can be used only with cards of the co-laminated type, and cannot be used with moulded cards. Now, a majority of cards are presently manufactured by the moulding technique for reasons of manufacturing convenience. The moulding material is generally polyvinyl chloride. It may also be ABS.